Ball piston pump



May 11, 1954 H. GERKEN 2,678,003

BALL PISTON PUMP Filed June 20, 1951 4 Sheets-Sheet 1 23 I2 34 I 17 33 cr1- zr 60 INVE/V ran.-

HEINRICH GERKEN BY M. A ATTORNEf y 11, 1954 H. GERKEN- 2,678,003

BALL PISTON PUMP Filed June 20, 1951 4 Sheets-Sheet 2 Fig. 5

Fig. 4

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77 Fig.6 30

rroa/v May 11, 1954 H. GERKEN 2,678,003

BALL PISTON PUMP 1 HEINRICH GER/(EN May 11, 1954 GERKEN I 2,678,003

BALL PISTON PUMP Filed June 20, 1951 4 Sheets-Sheet 4 Fig. 10

IN VE N TOR:

HEINRICH GE PK E N B) A I Arrow/5 a:

Patented May 11, 1954 OFFICE BALL PISTON PUlllP Heinrich Gerken, Mollnin Lauenburg, Germany Application June 20, 1951, "Serial No. 232,644

Claims priority, application Germany July 14, 1950 8 Claims. 1

This invention relates to ball piston pumps and compressors operating onthe universal joint principle and comprising a spherical rotor, a driveshaft having a slide and a stub shaft having a slide, the slidesindividually slidably engaging grooves in said rotor, and means foradjusting the discharge of the pump or compressor by shifting said stubshaft in a plane including the axis of said stub shaft and the axis ofsaid drive shaft and thereby varying the angle between said stub shaftand said drive shaft, all as more fully described hereinafter and asclaimed.

The discharge of rotary ball piston pumps and compressors operating onthe universal joint principle may be varied and adjusted by changing theposition of the stub shaft relative to the drive shaft, as is wellknown. In previous attempts to provide such adjustability of the stubshaft and overcome the sealing difiiculties involved therein, thebearing for the stub shaft was placed in a member that could be rotatedfrom the outside of the pump casing for purposes of dischargeadjustment. On such rotation of the bearing member, the stub shaft wasrotated around the axis of the drive shaft, i. e. out of a plane passingthrough the drive shaft and the position of the stub shaft prior to theadjustment.

Such rotation changed the pump chambers with-' out changing the anglbetween stub shaft and drive shaft. In all adjustment positions exceptthe one resulting in maximum pump discharge, each chamber would firstsuck fluid from the inlet and then again return at least part of thissucked-out fluid to the inlet. Such arrangements are not efficient anddo not permit fine adjustments to be made.

Th objects of this invention are to provide efficient and accurate meansfor adjusting the discharge of rotary universal joint principle pumps;to provide such means permitting fine and stepless adjustment; toprovide an arrangement in which the sealing problem is effectivelysolved; and to provide visual means for observing the adjustmentposition.

According to this invention, th foregoing objects are achieved byproviding an arrangement that permits varying and adjusting the anglebetween the stub shaft and the drive shaft in a given plane. It mightappear as if that could simply be accomplished by adiustably positioningthe stub shaft bearing in a slot provided in the pump casing. Suchsimple solution, however, is not practical because, aside from thsealing difficulties involved, in order to provide adequate range ofadjustment, the slot would have to be so long that it would interconnectthe inlet and outlet chambers which, of course, would make the pumpinoperative.

The main feature of this invention is a novel bearing arrangement forthe stub shaft employing two rotatable members, one being rotatable in abearing in the pump casing co-axial with the drive shaft and beingprovided with an eccentric bore, and the other rotatable member beingrotatabl in said bore and having therein an eccentric bearing for thestub shaft. The axes of both rotatable members and of the stub shaftbearing pass through the center of the spherical rotor. Means areprovided on the outside of the pump casing for rotating, directly orthrough a suitable transmission, the rotatable member that is rotatablein the bearing provided in the pump casing, in order to adjust the anglebetween stub shaft and drive shaft by shifting the stub shaft in theplane passing through both shafts. To this end, the turning motions ofthe two rotatable members are interlocked by the use of spur or wormgearing, guides or linkages. This arrangement makes it a simple matterto seal off the joints at the rotatable members. The face of the secondrotatable member can be made spherical-convex to engage aspherical-concave surface of the cover screwed to the pump casing; thisprovides in every adjustment position of the stub shaft uniform specificpressure on the contact surfaces between the stub shaft bearing parts,the rotary members and the casing. The slot in the casing cover in whichthe stub shaft is guided can be covered by a window permittingconvenient inspection of the stub shaft position, i. e. of the dischargeadjustment.

The abovementioned objects as well as other objects of my invention willappear more clearly from the following description and from the appendeddrawings in which like numerals are used to designate like partsthroughout the several views, and. in which:

Fig. 1 is a view, partly in section along line !-I of Fig. 2, of a ballpiston pump according to my invention;

Fig. 2 is a view, partly in section along line 2--2 of Fig. 1, with thecover 36 removed;

Fig. 3 is a fragmentary view of the drive shaft member of the pump shownin Figs. 1 and 2;

Fig. 4 is a. view of the spherical rotor of the pump shown in Figs. 1and 2;

Fig. 4a is a side view of the member shown in Fig. 4 taken at a rightangle to said figure;

Fig. 5 is a fragmentary view of the stub shaft member of the pump shownin Figs. 1 and 2;

Fig. 6 is an assembly, partly in cross-section, of the parts shown inFigs. 3, 4 and 5;

Fig. 7 is a view of a modified pump, partly in section along line ofFig. 8;

Fig. 8 is a view, partly in section along line 88 of Fig. 7, with bothcovers removed;

Fig. 9 is a view of the cover 64 of the pump shown in Figs. 7 and 8; and

Fig. 10 is a view in section along line |3-|0 of Fig. 9.

Referring now to Figs. 1 to 6, the pump" according to my invention has acasing II with liners I2 and i3 forming a spherical chamber or cavity Mwith which inlet and outlet passages |5 and I3 communicate and inwhich aspherical rotor H is disposed.

As shown in Fig. 4, the rotor ll has'four fiat faces |8 located 90degrees apart from each other (only three being visible in Fig. 4), andtwo grooves i9 and 23 disposed at right angles to each other, eachextending through an are greater than 180 degrees and being faced'ateachend, as indicated at 2|. This leaves narrow land areas 22 between themiddle portion of groove l9 and the ends of groove 23 (and vice versa)preventing short-circuiting of the fluid being pumped between the inletand outlet passages l5 and Hi.

The rotor may be described in other words as being formed by a spherewhose diameter is that of the land areas 22 and into which a groove 19extending 270 around the center of the sphere and a groove 29 aremachined, the latter extending also 270 around the center of the sphereand being at a right angle to the groove i9. Thebottoms of the groovesform surface portions of a smaller sphere I'l which is concentric withinthe larger sphere. The middle portions of the grooves taking up aboutone third ofthe aforementioned 270 have parallel side wall portions l8,the parallel side wall portions of groove |9 being in planes at a rightangle to the parallel side wall portions of groove 29. The parallel sidewall portions are connected with the bottoms of the grooves by inclinedsurfaces |8 forming an angle of 90 whose point coincides with the centerof the spheres. The side walls 2| of the ends of the grooves are acontinuation of the inclined surfaces I8" of the middle portion of thegrooves and are parts of surfaces of right angled cones whose apexcoincides with the center of the spheres.

The drive shaft member, shown in Fig. 3, consists of a drive shaft 23with a fiat side 24 connected thereto and adapted to fit into groove E9.The slide 24 comprises two horns 25, only one of which is visible inFig. 3. The drive shaft 23 is rotatable in a bearing 23 formed in thepump casing and more specifically in the liner I2 (see Fig. 1). A stubshaft member, shown in Fig. 5, consists of a stub shaft 21 with a flatslide 28 connected thereto and adapted to fit into groove 23. The slide28 comprises two horns 29 and 39. The stub shaft 27 is mounted in abearing (to be described later) in such manner that it is inclined at anangle A to the axis of drive shaft 23. The extension of grooves |3 and23 through arcs greater than 180 degrees provides relatively large guideand sealing surfaces for the slides 24 and 28.

In the assembled pump there are formed four similar chambers between thefaces 2| of the grooves I9 and 29 on the one hand, and the ends of horns25, 29 and 33 on theother hand. During operation, the drive shaft 23 isrotated by any suitable power means (not shown). The slide 24, connectedwith shaft 23, causes the rotor H to rotate. The rotor I! in turn,through slide 28, imparts rotation to stub shaft 2i. Due to the angulardisposition of stub shaft 2! relative to drive shaft 23, however, anoscillating. motion is imparted to the rotor during its rotation,causing the aforementioned chambers to open and close during eachrevolution of the drive shaft 23. In Fig. 1, one such chamber is shownat 3| in the open condition, and another at 32 in the closed condition.Consequently, as the drive shaft 23 and with it rotor revolves, saidfour chambers open and close to produce a pumping action; opening-onsuction and closing on discharge to givefour discharges per revolution.

It is apparent that the discharge of the pump can be regulated byvarying the angle A between the drive shaft 23 andthe stub shaft 21. Themeans for providing adjustability of the stub shaft form themainfeatureof this invention.

As shown in Figs. 1 and 2, a rotatable bearing member 33 haseccentrically formed therein a bearing 34" for the stub shaft 27, thelatter extending into and being guided by a slot 35 in a cover 36attached to casing |l. Another rotatable member 3! is rotatable in abearing 38 formed in casing co-axially with the drive shaft bearing 26.The rotatable member 3'! has eccentrically formed therein a bore 39 inwhich the member 33 is rotatable. The previously mentioned angle Abetween the drive shaft 23 and the stub shaft 21 consists of the sum ofangle 13 between the stub shaft bearing 34 and the axis of rotatablemember 33 plus angle C between the axis of bore 39 and. the axis ofbearing 38, said angles 13 and C being preferably equal. The axes ofbore 39 (and rotatable member 33) and of bearing 34 (and stub shaft 2'!)both pass through the center of the spherical rotor IT, as clearly shownin Fig. 1.

The rotatable member 33 carries a gear 49 meshing with a bevel gear 4|which, together with a spur gear 42, is mounted on a sleeve 43 rotatableon a shaft 44 on rotatable member 3?. Another spur gear 45, rotatable ona shaft 46 on rotatable member 31, meshes with the spur gear 42 and withan internal gear 41 fixed to casing The rotatable member 31 has attachedthereto a worm gear 48 meshing with a worm 49 on shaft 59 extending tothe outside of casing H and provided with a knob 5|.

By manually turning knob 5|, the rotatable member 31 may thus be rotatedin a clockwise direction as indicated by arrow 52 in Fig. 2. This causesspur gear 45, rolling on internal gear 41, to turn in a counterclockwisedirection as indicated by arrow 53. Spur gear 42, meshing with spur gear45, consequently rotates clockwise, as shown by arrow 54, and bevel gear4| rotates with it, causing the gear 49 and, with it, the member 33 torotate counterclockwise, as indicated by arrow 55, while, at the sametime, the axis of bore 39 in which member 33 turns, rotates clockwise,being located in member 31. Due to these interlocked movements, the stubshaft 21, guided in slot 35, moves in the plane (that is in the plane ofFig. 1) as indicated by arrow 56, until eventually the positions shownin broken lines in Fig. 2 are reached, wherein the drive shaft 23 andthe stub shaft 21 are co-axial and the angle A is zero. With thisadjustment, the previously described oscillating motion of the rotorceases, the chambers 3| and 32 become 5. equal in size, and thedischarge of the pump is zero. Further turning of the knob in the samedirection brings the stub shaft '27 below the axis of the drive shaft 23and causes the pump to discharge again, but now in a reverse directionso that what formerly was the inlet is now the outlet, and vice versa.

It should be emphasized that the shifting of the stub shaft, i. e. thechange in the angle A, takes place in the plane of Fig. 1. It isapparcut that attainment of tight seals between casing II and rotarymember 8'! on the one hand, and between rotary members 3i and 33 on theother hand, presents no problem, especially if packing rings 51 and 58are provided, as shown in Fig. 1. The face 59 of the rotary member 33 isconvex-spherical and engages a concavespherical surface 60 on the insideof cover 36, so that a tight joint between these parts is likewiseprovided. Since the adjustment of stub shaft 2 is attained by rotationof circular surfaces, the specific pressure on all bearing surfaces ofthe parts of the adjustment mechanism is equal in all angular positionsof the stub shaft 21.

In Figs. 7 to ii) are shown modifications of the pump and of themechanism for adjusting the stub shaft. In this arrangement, thespherical rotor consists of two hollow halves 5i and 62 jointed togetherby a central member 63 which is connected to both halves 6i and 52 bysuit able screw means (not shown). The pump casing H with liners l2 andit, drive shaft 23 with slide 24, stub shaft 2'! with slide 28,rotatable members 3"! and 33 including stub shaft bearing 3d are likethose of Figs. 1 to 6, as are the means for rotating the member Bl,comprising worm gear 48, worm E9, shaft 5B, and knob 5i.

However, the mechanism for interlocking the rotary motions of rotarymembers 33 and 3"! to provide shifting of the stub shaft 2.? in a givenplane is different from the gearing arrangement shown in Figs. 1 and 2,although the same resuit is attained. ing i i has attached thereto byscrews (not shown) cover 54 with a concave-spherical surface 65concentric with rotor 5!, E2 and engaging the convex-spherical surface59 on rotatable memper 33. In the cover 64 is provided a slot 66(similar to slot of Fig. 1) through which the stub shaft 2? passes. Thecover 64 has, furthermore, three diametrically extending grooves 5'5, 68and 59 which are disposed at angles of degrees to each other and to slot65, as clearly shown in Figs. 9 and 10.

The rotatable member 33 is provided on surface 59 with three guide pinsiii, H and 12 which may be formed integrally on member 33, as shown, orwhich may be separate rods press fitted or screwed into suitable holesin member 33. The guide pins m, ii and '52 are arranged to slide backand forth in grooves 67, 68 and 65, respectively. For a clearerunderstanding, the slot 66 and the grooves 51, t8 and 69 have beenindicated in Fig. 8 by dash-dotted lines.

With the stub shaft '2'! at its maximum elevation in which its axisincludes the angle A with the axis of bearings 26 and 33 the rotarymember 33, stub shaft 2! and guide pins ill, "H and i2 occupy thepositions shown by solid lines in Fig. 8. On rotating the rotary member37 in a clockwise direction, as indicated by arrow it, by turning theknob 5! or by other suitable means, the rotary member 33, resting in theIn this modification, the cas- 6. eccentric bore 39 of member 31, isforced to rotate counter-clockwise, as indicated by arrow Hi. Duringsuch rotation of member 31 through 90 degrees, the guide pin l0 movesthrough groove t! in the direction of arrow '55 to the dotted posi-=tion; the guide pin H moves through groove fit in the direction of arrowE5 to the dotted position; the guide pin 22 moves through groove 69, atfirst in the direction of arrow Ti, then stops, and returns to theposition shown in solid lines; the stub shaft 2? moves through slot E55in the direction of arrow '58 to the position formerly occupied by guidepin "H; and the rotatable member 33, in addition to itscounter-clockwise rotation, shifts to the position indicated by dottedlines. In this new position, the angle A becomes zero, i. e. the axes ofdrive shaft 23 and stub shaft 21 coincide. When that occurs, thedischarge of the pump becomes zero, as has been fully explained inconnection with Figs. 1 to 6.

If rotation of rotatable member 3'! is continued beyond 9O degrees, thestub shaft 27 moves downward in slot 66 below the central position andthe pump begins to discharge again at a gradually increasing rate, butin a reverse direction, as previously explained. During this continuedrotation ofmember 37, the guide pin '59 moves in groove 67 at firstfurther in the direction of arrow 15, then reverses its motion andreturns towards the dotted position; the guide pin H moves in groove 63in a directionopposite to that indicated by arrow towards the solid lineposition; and the guide pin '52 moves in groove 59 in a directionopposite to that indicated by arrow ll through and beyond the center. Ifthe rotation of member 31 is continued through another degrees, theangle between the axis of stub shaft 21 and the axis of bearings 26 and33 reaches its maximum value A. Thus, with this modification, as withthe embodiment shown in Figs. 1 to 6, the stub shaft 2'! may besteplessly adjusted. from maximum angularity on one side through zero tomaximum angularity on the other side, whereby the pump discharge isvaried from maximum rate of flow in one direction through zero tomaximum rate of flow in the opposite direction.

In the arrangement of Figs. 'l-to 10, additional cover means 19 areprovided to cover up the end of stub shaft 2? projecting through slot66, the cover means 19 being fitted with a window 88 co-extensive withslot 66 to permit observation of the position of stub shaft 2'! in slot66, indicative of the pump discharge adjustment.

A particular advantage of the stub shaft ad justment according to myinvention is that it permits a fine, stepless adjustment such as hasbeen unattainable hitherto. When pumping highly viscous or more or lesscongealing liquids, my adjustment makes it possible to vary thedischarge and with it the power requirement of the pump to match thecapacity of the drive motor and so avoid overloading the motor. Theusefulness of my novel adjustment is, of course, not confined to theexact type of universal joint principle pump shown, but extends to othertypes such as those employing pin joints between shafts and rotor inplace of the cooperating slides and grooves herein disclosed.

While I have shown and described what I consider the preferredembodiments, I realize that modifications other than those disclosedherein may be made without departing from the spirit of my invention,and reference is, therefore, made to the following claims for adefinition of the scope of my invention.

What I claim is:

l. A ball piston pump comprising a casing having a spherical chambertherein and an inlet and an outlet for said chamber, a solid sphericalrotor slidably concentrically fitted in said chamber and having twolongitudinal grooves in its surface, said grooves being disposed at aright angle to each other, two flat substantially semi-circular s1idesslidably fitted in said grooves, each slide having a spherical outersurface portion slidably concentrically fitting in said chamber, a driveshaft connected with one of said slides, a stub shaft connected with theother of said slides, and means movably connected with said casing forshifting said stub shaft with the slide to which it is connected in aplane containing the axis of said stub shaft and the axis f said driveshaft and thereby varying the angle between said stub shaft and saiddrive shaft.

2. A pump as defined in claim 1, each of said grooves extending throughan arc greater than 180 degrees and having end faces substantiallyconforming with the end faces of said slides.

3. A pump as defined in claim 1 comprising two co-axial bearingsdisposedin said casing on opposite sides of said rotor, said drive shaft passingthrough one of said bearings, a 1'0- tatable member independent of saiddrive shaft and extending through the other of said bearings, a bore insaid rotatable member having an axis passing through the center of saidspherical rotor and inclined to the axis of said bearings, bearillgmeans rotatably fitted in said bore and comprising a bearing for saidstub shaft, said hearing having an axis passing through the center ofsaid spherical rotor and inclined to the axis of said bore, and meanssupported in and extending to the outside of said casing for rotatingsaid rotatable member.

4. A pump as defined in claim 3, said last named means comprising a wormgear attached to said rotatable member, a worm meshing with said Wormgear, a shaft for said worm supported in and extending to the outside ofsaid casing,

and means connected with said last named shaft for rotating said lastmentioned shaft.

5. In a pump as defined in claim 3, a cover for said casing, a slot insaid cover, said stub shaft extending through and being guided in saidslot, a concave-spherical inside surface on said cover, and aconvex-spherical outside surface on said bearing means slidably engagingsaid concavespherical surface on said cover.

6. In a pump as defined in claim 3, an internal gear fixed in saidcasing, a pair of intermeshing spur gears rotatably mounted on saidrotatable member, one of. said spur gears meshing with said internalgear, and means cooperating with the other of said spur gears to rotatesaid bearing means.

7. In a pump as defined in claim 3, a cover for said casing, a slot insaid cover, said stub shaft passing through and being guided by saidslot, three grooves extending diagonally across said cover and beingdisposed at angles of degrees to each other and to said slot, and threeguide pins on said bearing means, each of said guide pins being arrangedto slide back and forth in one of said grooves on rotation of saidrotatable member.

8. In a pump as defined in claim 7, cover means mounted over said cover,and a window in said cover means co-extensive With said slot.

References Cited in the file of this patent UNITED STATES PATENTS NumbeName Date 1,150,430 Hamann Aug. 17, 1915 1,613,210 Warschan Jan. 4, 19271,678,050 Kearney July 24, 1928 2,040,178 Kempthorne May 12, 19362,353,780 Neuland July 18, 1944 2,525,907 Johnston Oct. 17, 1950 FOREIGNPATENTS Number Country Date 333,256 Italy Dec. 24, 1935 349,756 ItalyJan. 21, 1937

